Thread-controlling mechanism for sewing-machines



R BECKER. I THREAD CONTROLLING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED NOV-.25, I918.

Patented Aug. 2, 1921,

3 SHEETS-SHEET l- INVENTOR f WITNESSES A TORNEY R. BECKER.

THREAD CONTROLLING MECHANISM FOR SEWING MACHINES. APPLICATION F|LED NOV. 25. 1918.

1,386,307, Patented Aug. 2, 1921.

3 SHEETS-SHEET WITNESSES INVENTOR 7 7 W W Y A ORNEY R. BECKER.

THREAD CONTROLLING MECHANISM FOR SEWING MACHINES.

, APPLICATION FILED NOV. 25, 1918- 1,386,307, Patented Aug. 2, 1921.

3 SHEETS-:SHEET 3- IIIIIIIIIIIIIIII:

- F: d f

INVENTOR ATTORNEY UNITED STATES PATENT OFFICE.

RUDOLPH BECKER, OF ROSELLE PARK, JERSEY, ASSIGNOR TO THE SINGER MANUFACTURING COMPANY, A CORPORATION OF NEW JERSEY.

THREAD-CONTROLLING MECHANISM FOR SEWING-MACHINES.

Specification of Letters Patent.

Patented Aug. 2, 1 921.

Original application filed November 5, 1917, Serial No. 200,273. Divided and this application filed No vember 25, 1918.

T 0 all whom it may concern:

Be it known that I, RUDOLPH BECKER, a citizen of the United States, residing at Roselle Park, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Thread- Controlling Mechanism for Sewing-Machines, of which the following is a specification, reference being had therein to th accompanying drawings.

This invention relates to sewing machines and particularly to mechanism for controlling the thread during the formation of stitches, being a division of application Serial No. 200,273, filed November 5, 1917.

The invention is directed particularly to a new and useful mechanism for controlling the thread of a straw braid sewing machine of a type which has met with wide satisfaction and in which a pair of upwardly directed needles, one apertured and the other hooked, penetrate through the work from its lower side and on the upper side of the work cooperate with loopers or other thread handling mechanism to form a chain stitch in. which only short lengths of thread appear on the fair side of the goods at relatively widely spaced intervals.

The invention aims to provide a better control of thread in this type of machine than heretofore and enables different lengths of stitches being set properly and without special adjustment of the thread controlling mechanism, thereby decreasing the amount of work the operator has to do and insuring the proper formation of a stitch on any and all machines that may be in the factory regardless of the length of stitch that is best suited to the character of the braid being formed into a hat.

The construction comprises essentially an eye-ended take-up arm arranged to vibrate bet-ween a pair of thread-guides and a nipper or thread-clamp which intermittently grips the thread, boththe take-up and the nipper being governed and automatically adjusted from a common lever, preferably the feed regulator.

The invention is illustrated inthe accompanying drawings, inwhich Figure 1 is a front side elevation of the machine. Fig. 2 is a transverse section through the lower part of the frame of the machine showing the feed regulator and one side of the take- Serial No. 263,990.

In). Fig. 3 is a detail in cross section showing the other side of the take-up. Fig. l is a sectional detail of the nipper. Fig. is a plan view of a barrel portion of the nipper. Fig. 6 is a rear side elevation looking at that portion of the frame of the machine on which the nipper and take-up are mounted. F1g. 7 is a diagram of the stitch, the successive stitches in the formation of which are illustrated in Figs. 8 to 11 inclusive and Fig. 12 is a diagram representing the rela tive motion of the eyes of the needle and take-up on both long and short stitch.

The invention is illustrated applied to a straw-braid sewing machine having an eyepointed needle 1. and a hook n edle 2 actuated by suitable mechanism such as is fully disclosed in my previously mentioned parent application Serial No. 200,273 which also discloses a suitable form of presser-foot and looper mechanism. The feeding mechanism, as more fully disclosed in said parent case, may include a feed rocker 3 hinged on the shaft 4- and having a slot 5 receiving a slide-block 6 whose position therein is vari able to change the length of stitch.

The position of the slide-block 6 in the slot of the feed-rocker is governed by a feed regulator in the form of a lever 7, Fig. 2 pivoted on the main-shaft 8 adjacent the feed-eccentric 9 and having a fork 10 curved as shown at the end of its long arm embracing afriction roll 11 carried by the block 6 in the slotted feed-rocker 3 so that the operator is enabled on manipulating the opposite end of the lever to shift the block to and from the fulcrum of the feed-rocker to vary the length of feed or stitch.

Convenient control of the feed regulator is provided by extending a pin 12. Figs. 2 and 3 secured in the short arm 13 of the lever through a slot 14 in the front wall of the frame in register with which slot is a correspondingly shaped opening in a segment plate 15 secured by screws 16 to the frame and provided on opposite sides of the elongated opening with series of sockets 17. A handle 18, Fig. 3 is sleeved on the end of the pin 12 and a coiled spring 19 is interposed between the bottom of the socket in the handle and the head of a screw 20 threaded into the pin. A pair of diametrically disposed pins 21, Fig. 2 are arranged adapted to seat in the sockets 17 in the plate. These sockets and pins may be of such size, shape and spacing as to permit of any desired variations in the length of stitch.

The thread controlling mechanism comprises a take-up and a nipper located on the front wall of the frame convenient to the set-screw 27 in one endof a lever 28, Figs.

- frame.

2, 3 and 6, which is fulcrumed intermediate its= ends as shown at 29 to a rock-arm 30 which in turn is fulcrumed on the pin 31 fixed horizontally in the central web below and in. front ofthe main-shaft of the :machine. The lever 28 and the eye-ended arm 26 together constitute the take-up proper and move as one. For actuating the takeup a pitman 32; connects the lower end of: they lever 28; with an eccentric 83 on the main-shaft while a link 34: connects its upperend with a pin 35 securedrby a setscrew 36 in a lug 37 integral with the eccentric-strap embracing the feed eccentric 9. When the feed is regulated the action of the take-up is variedsimultaneously with that of the nipper by reason of the angular rotation of oneend of the link 34-h about the center of: the feedactuating eccentric.

The nipper, see Figs. 1-, 5 and 6, comprises'a clamping head or button 38, whose stem 39 -is threaded into the end of a pitman 4:0 strapped about an eccentric 4:1 on the main-shaft, and an adjustable abutment which embraces the stem. This abutment consists of a cylindrical barrel 42 in whose outer wall is an inclined slot 43 receiving the stud end 44: of a screw i5 tapped into the An arm 46, Fig. 6 fixed to the rear end of this barrelhas a forked extremityi? embracing the pin 12in the manipulating end of the feed regulator. When the feed ischangedthe barrel is turned by 'means of this arm forked about the feedqregulator and the inclination of the slot in the barrel is-such that nipping of the thread is timed to occurlater when the stitch is long than when-it is short and vice versa. Sothat the thread will not be crushed and in order to allow the meeting faces of; the abutment and clamping, head to come together squarely, a; washer 48, Fig. '4 is loosely mount-ed;infthebarrell A spring 49 of the proper-strength resting on the rear end of the barrel, thrusts the washer toward the" clamping head or button-and against .the in- .tu-rned restrainingflange-oQ at the front end of the barrel.

A. constant tension device 51 of any suitable form is secured on the front wall of the vertical standard and thread from any suitable source-is passed through'this tension de vice, through threadreyes 52,53 on opposite sides of the nipper, through the thread-eyes setat an inclination in a horizontal plane in the frame with its. delivery end adjacent the path in whichthe needles reciprocate. The thread is then p'assed up along the groove in the needle 1 and through its eye.

The operation ofthe thread-controlling mechanism will now be described.

YVhen. the needles enter and pass up through the work they draw upon the previously formed loop which has been shed by the hook and left encircling the shank of the eye-pointed. needles In the case of long stitch the previously formed loop is already tight or nearly soandv thread is consequently; drawn by theQeye-pointed needle from the supply, the nipper of course being open to permit such drawing action. In the case of; agshort stitch thepreviously formed loop is not snug about the shank of the eye its highest position to a position beneath the work supplies the same amount of thread for the stitch being formed whether it be long or short. In the case of a short stitch the needlesupplies too much thread and inthe case of a .longstitchit' does not supply enough thread. Thus the thread controlling mechanism is called upon to perform a functionlin making a short stitch that is diametrically opposed to the function it mustper form in making a long stitch. This is to say, in the case of a long stitch the threadcontrolling mechanismmust function mainly as a pull-oifto meet a deficiency of thread and in'the case of. a short stitch mainly as a take-up to handlean excessof'thread. Consequently while theneedles are moving 'below. the workand during the feeding action, thread is given up (when a long-stitch is beingmade) by the 'arm'26 as it rises toward the line of the fixed eyes 22and ;is taken up (when a short stitch is being made) by'the arm 26 asit'movesv above and away from the lineiof the eyes22; This will be clear from anexamination of the curvesshown in Fig. '12 with'out further explanation. These ci 1rves..graph-ically. express the thread-control" throughouta stitch-forming cycle, and

22, and the eye of the take-up to a tube 54: V

may be distinguished by the abbreviations N. E., T. L. and T. S., which respectively represent the movement of the needle-eye, the take-up on a long stitch and the take-up on a short stitch.

It is to be noted that the needle-eye curve N. E., Fig. 12 was plotted from the machine with the presser-foot removed and consequently the maximum height of the needleeye above the throat-plate therein shown is less than it would ever be in actual practice with the material under the presser-ioot. It is to be noted also that vertical distances in Fig. 12 represent the actual travel of the needle-eye and take-up eye while the diagrammatic views in Figs. 811 inclusive are double the actual size. In Fig. 12 the duration of nip and of feed are also indicated.

It will be seen that the thread-controlling mechanism comprises a variable nipper and a variable take-up. The grip of the nipper varies from almost nothing on a long stitch to about a third of a revolution of the mainshaft on a short stitch. The throw of the take-up on a long stitch is a little less than its throw on a short stitch but its vibrations are largely below a line connecting the adjacent fixed eyelet-s 22 in the case. of a long stitch whereas they are largely above the same in the case of a short stitch. By the simple arrangement for effecting this change in the movement of the take-up arm 26 together with the duration of the nippers grip upon the thread, the action of the eyed arm 26 during a long stitch is substantially that of a pull-off and during the formation of a short stitch is substantially that of a take-up.

By making the variations in the stroke of the needle take place solely at the upper end or" the stroke it will be seen that the eyepointed needle will draw off more thread when the work increases in thickness than in the machines of the prior art in which variations in the needles stroke occur at both ends of its stroke. Obviously increasing the drawing action of the eye-pointed needle when the work increases in thickness meets the demands of seamformation bet ter than the organizations in the prior art having the same type of controlled needle operating mechanism.

The wire from which the eyes 22 are bent or formed is preferably light enough to permit of a slight spreading or separation of the eyes when the strain put upon the thread running to the take-up is the greatest, as it is when a short stitch is being made and the take-up is in the position shown in Fig. 1.

Due to the adjustability of the eccentric 33 for the take-up, the eccentric 4:1 for the nipper, and the thread-eyes 22 the proper relative timing and the extent as well as the duration of action of these thread-controlling elements may be varied to suit the exact requirements of the stitch for various kinds of work. It is also to be noted that the eccentric (or crank equivalent) actuation of the take-up and of the nipper enables a machine of this type attaining a higher speed than those heretofore in use equipped with a cam driven take-up or nipper.

Having thus set forth the nature of the invention, what I claim herein is 1. In a sewing machine having stitchforming and \\*oi'l feecli11g mechanism, in combination, a take-up, a nipper, and means for simultaneously varying the extent of the take-ups throw and the timing of the nip ping action.

2. In a sewing machine, stitch-forming and worlcfeeding mechanism, thread-controlling mechanism including a take-up and a nipper, devices for varying the length of feed, and means governed by said devices for changing the action of both the take-up and the nipper whereby the stitch may be formed properly conformably with its length.

3. In a sewing machine having stitchforming and work feeding mechanism, thread-controlling mechanism including a take-up and a nipper, a lever for varying the action of the work-feeding mechanism to change the length of stitch, and means governed by said lever for changing the action 01" the nipper and the take-up to suit dif ferent lengths of stitch.

1. In a sewing machine having a mainshaft and stitch-forming mechanism, work feeding mechanism including a slotted feedrocker, an eccentric element on said mainshaft, a strap connected to said eccentric element and also adjustably connected to said slotted rocker, a. lever for adjusting said strap to vary the angular displacement of said slotted feed-rocker, a pin carried by said strap. a take-up lever fulcrumed on a movable support, a link connected to said pin, a second eccentric element on said mainshaft and a pitman connected thereto, said pit-man and link being joined to said takeup lever on opposite sides of its movable fulcrum support.

5. In a sewing machine having a main shaft and stitch-forming mechanisr workfeeding mechanism. and threadrontrolling mechanism including a take-up and a nip per. spaced eccentrics on said main-shaft for separately operating said take-up and said nipper, a "feed-regulator, and means governed by said feed-regulator for altering the action of both said take-up and nipper when the feed is changed.

6. In a sewing machine, a main-shaft, stitch-forming mechanism, work-feeding mechanism, and thread-controlling mechanism including a nipper, said nipper having a clamping head actuated from said mainshait, an adjustable abutment cooperating with the clamping head, a feed-regulator, and means governed by the feed-regulator for varying'the position of the abutment relative to the clamping head.

I 7. in a chain stitch machine having eye- 'pointed and hooked needles arranged in tandem and cooperatinglooper mechanism, adjustable work-feeding mechanism, and

' thread-controlling mechanism including a nipper, a pair of relatively fixed thread guides and a thread-carrying arm movable therebetween, and means for varlably actuating said thread-carrying arm in coopera-.

tion with the nipper to mainly pull oil thread for a long stitch and to mainly take up thread for a short stitch.

S. Ina chain stitch machine having eyepointed and hooked needles arranged in tandem and cooperating looper mechanism, adjustable work-feeding mechanism, and thread-controlling mechanism including a variable nipper, a pair of relatively fixed.

thread-guides and. a thread-carrying arm movable therebetween, and means forthrowing said thread-carrying arm mainly to one side of the line of said fixed thread-guides on a long stitch and mainly to the opposite side of the line of said fixed thread-guides on a short stitch whereby the thread-com trolling mechanism functions mainly as a pull off on along stitch and mainly as a take-up 011 a short stitch.

. 9. In a straw braid-machine having eyepointed and hooked needles, in combination, feeding mechanism, means for adjusting the feeding mechanism, nipping mechanism,

take-up mechanism, means for adjusting the nipping and take-up mechanisms, eccentric elements for actuating said nipping and take-up mechanisms, and operative means connecting the feeding mechanism and they adjusting means for the nipping and takeup mechanisms.

7 10. In a straw braid machine having eyepointed and hooked needles, in combination,

feeding mechanism, nipping mechanism, and. a take-up including a lever fulcrumed 1ntermediate its ends, controlling means includ ing a link secured to one end ofsaid'lever and to the feeding mechanism, and eccentric operated means for actuating the other end out said lever, and means for adjusting said link to vary the movement of the take-up.

12. In a straw braid sewingmachine having eye-pointed and hooked needles whose lower limit of movement isfixed, "in combination feeding mechanism, means for adjusting the feeding. mechanism, thread-controlling mechanism including a nipper and take-up, and means connected with the'i'eeding mech-.

.anism for automatically adjusting said 112L118? up whereby it will act in cooperation with the nipper mainly as a pull-off for the thread when a long stitch is made and as a,

take-up for the thread when a short stitch is being made. i i

13. In a straw braid sewing machine having eye-pointed and hooked needles whose lower limit of'movement is fixed, in combination, feeding mechanismand threadcontrolling mechanism comprising a 'nipper, relatively fixed, take-up eyes and athreadcarrying arm movable therebetween, means for operating said nipper to, grip the thread but once during each stitch-forming: cycle and means connected with the feeding mechanism for automatically varying the action of the .tln'ead-carrying' arm with variations in the length or the stitch.

14. In a sewing machine having stitch.-

forming mechanism, work-feeding mechanism, a regulator therefor, thread control ling mechanism including a nipper having cooperating thread clamping elements, means for operating one of said elements and means governedby the feed-regulator. for adjusting the other of'said element-s.

15; Ina sewing machine having stitchforming mechanism, work-feeding mechanism and a regulator therefor, thread controlling mechanism. including a 'nipper,

means for operating the nippier and means controlled by the teed-regulator but acting independently of the nipper operating means for varying the timing ofthe nipping action.

In testimony whereof'I have signed my name to this specification.

. i l U OLPH. BECKER. 

